The present invention relates to communication networks. More particularly, the present invention relates to an apparatus and method of integrating communication among communication networks and devices that implement disparate protocols so that both real-time traffic and best-effort traffic may be exchanged over a common medium.
Currently, individuals have a myriad number of different ways of communicating with each other. Typically, data pertaining to the myriad number of forms of communications fall into two broad traffic classes. The first traffic class is real time communication, which pertains to data transmission having a low and/or deterministic delay. Real time communication is typically provided by telephone networks or proprietary networks that can guarantee end-to-end bandwidth availability for a given data flow. The second is non-real time, best effort communication, which pertains to data that do not require transmission in real time. Best effort communication, such as the transmission of non time-critical data files, typically takes place as bandwidth becomes available over a network. Currently, best effort communication may take place through a computer network or a global network like the Internet.
Because these two separate data classes have different bandwidth and delay requirements, they are typically implemented over at least two separate communication networks utilizing at least two different trunk resources. Accordingly, telecommunication companies (telcos) must then support two different communication networks for individuals to fully communicate with each other. The burden of supporting these two traffic classes becomes more challenging when incompatible communication devices employing disparate protocols are involved.
Typically, a communication network employs several layers of communication protocols in order to facilitate communications. Initially a communication network is based upon the type of communication medium. For example, a network may be based upon a twisted wire or fiberoptic communication medium. The first layer (layer 1 or physical layer) of communication protocol determines how communications are to be characterized over the communication medium, such as defining signal levels, transmission frequencies, etc.
The second layer (layer 2 or link layer) defines the formatting of information that is carried across the communication medium. The third layer (layer 3 or network layer) controls the routing of information within the communication network. Layers 4 through 7 perform additional functions between the network layer and a user to enable the user to carry out a communication. A more detailed description of communication protocol layers is presented in "Internetworking with TCP/IP, Principles, Protocols, and Architecture", by Douglas Comer, published by Prentice Hall, which is incorporated herein by reference in its entirety.
Thus, in addition to the necessity of supporting the inherent different voice and data communication networks, telcos and organizations must deal with the possibility of having to support different communication protocols, especially different physical layer (layer 1) and link layer (layer 2) protocols, between different networks.
To facilitate discussion, FIG. 1 illustrates an exemplary prior art method of providing real time and best effort communication between two individuals 30 and 60. In the illustrated example, a data network 70 and a telephone network 80 provide best effort and real time communications, respectively, between offices 10 and 40.
Data network 70 is useful for exchanging files, data, and other types of communication that do not require low and/or deterministic delay guarantees. Data network 70 may include a public data network 71, such as the Internet, and a private data network 72. Public network 71 is typically useful to allow communication between each of individuals 30 and 60 with a myriad number of services through various Internet service providers and servers, such as Internet server 78. Also, individuals 30 and 60 may be able to communicate with one another through the resources of public network 71.
However, if individuals 30 and 60 belong to the same organization or commonly communicate with each other, a private data network 72 may be utilized. A private data network may be implemented for best effort data in order to ensure improved security, bandwidth availability, and reliability relative to the public network. In the example of FIG. 1, private data network includes trunk resources such as data trunk lines 73(0)-73(n). Typically, data trunk lines 73(0)-73(n) are T1 or DS3 unchannelized data lines that are provided or leased by, for example, a telecommunications service provider. Data communication through data network 70 typically takes place in an asynchronous manner.
Each router 12 and 42 are typically connected to a number of communication devices, such as local area network (LAN) switches 16 and 46 and servers 19 and 49. Computers 17, 18, 47 and 48 may also be coupled to LAN switches 16 and 46. Thus, individual 30 through computer 18 may conduct communications with individual 60 through computer 48 and the devices and networks coupling the two computers. Again, the form of communications permitted by the data network is typically limited to best effort communications.
When real time communications is desired, a synchronous communication network is typically employed. As mentioned before, real time traffic, such as telephone conversations or real time video/audio data, require a data network that is capable of guaranteeing the required bandwidth and low/deterministic transmission delay. Because of these requirements, real time data communication typically takes place in a synchronous manner. Currently, the telephone networks (both public and private) provided by telecommunication service providers are typically utilized for real time communications.
Referring further to FIG. 1, offices 10 and 40 are typically connected to each other by a real time communication network 80 to facilitate real time communication. Real time communication network 80 may include a public switched telephone network (PSTN) 81 and/or a private real time communication network 82. PSTN 80 may represent, for example, the telephone network utilized by the telecommunications service provider, which allows communications to telephones 82 and 20(0 . . . n) through the public trunk resources.
Private real time communication network 82 typically consists of dedicated real time data trunk lines 83(0)-83(n) that connect the offices. Real time data trunk lines 83(0)-83(n) may represent, for example, channelized T1 or DS3 lines that offer 24 voice channels a piece. As in the best effort communication situation, the use of a private real time communication network provides improved convenience, bandwidth availability, reliability and security.
Generally, offices 10 and 40 include private branch exchanges (PBXs) 14 and 44 that are coupled to the public switched and private real time communication networks. The PBXs are in turn connected to a number of telephones 20(0)-20(n) and 50(0)-50(n). Individual 30 may, for example, utilize telephone 20(0) to communicate in real time with individual 60 through telephone 50(0) through either the private or public switched real time networks.
Thus, the prior art requires two vast and extensive communication networks and different communication mediums in order to facilitate data communication of both traffic classes (i.e., the real time and best effort traffic classes). As discussed in connection with FIG. 1, both asynchronous and synchronous communication networks may be required. For organizations desiring private networks, they (and the telcos that provide such networks) must contend with greater costs with regard to establishing and maintaining two separate private networks and sets of trunk resources in order to allow their employees to communicate in both real time and best effort methodologies. In many cases, the implementation of these different communication networks are closely tied to a specific link layer technology and protocols, requiring extensive investments in implementation, maintenance, and upgrade.
By way of example, individuals 30 and 60 and their organization must pay for the costs associated with maintaining two private networks 72 and 82 if both modes of communication are desired. At the same time, the telecommunications service provider(s) that provide the private data and telephone networks must bear the costs of implementing, maintaining, and upgrading two different sets of trunk lines and many different types of communication devices. Each time the underlying link layer technology changes, such upgrades can be very costly.
Therefore, there is desired an integrated service architecture for implementing real time and best effort communication using a common medium, e.g., the same set of trunk lines. A method of interconnecting communication networks employing different physical and link layer protocols is further desired.